SELECt source_id, company_id, MAX(avg_click) as max_click FROM (SELECt source_id,company_id,AVG(clicks) AS avg_click FROM table_companyGROUP BY source_id,company_idORDER BY avg_click DESC) tmpGROUP BY company_id

SELECt source_id, company_id, MAX(avg_click) as max_click FROM (SELECt source_id,company_id,AVG(clicks) AS avg_click FROM table_companyGROUP BY source_id,company_idORDER BY avg_click DESC) tmpGROUP BY company_id